Idiom meaning, usage examples, facts

1. My parents have been nagging at me to get a job for several months, and now, they’re turning up the heat. They’ve told me I’ll have to move out if I don’t get a job.
2. The lawyer turned up the heat and started to question the witness much more aggressively.

The expression suggests how pressure is created (or increased) when heat is applied to a pot of liquid on a stove.